Iterate on nodes instead of single bits to save node resolution for each
single bit.
Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
---
libsepol/src/ebitmap.c | 49 ++++++++++++++++++++++++++++++++++++------
1 file changed, 43 insertions(+), 6 deletions(-)
diff --git a/libsepol/src/ebitmap.c b/libsepol/src/ebitmap.c
index c3d706e9..e0541abb 100644
--- a/libsepol/src/ebitmap.c
+++ b/libsepol/src/ebitmap.c
@@ -116,14 +116,51 @@ int ebitmap_and(ebitmap_t *dst, const ebitmap_t *e1, const ebitmap_t *e2)
int ebitmap_xor(ebitmap_t *dst, const ebitmap_t *e1, const ebitmap_t *e2)
{
- unsigned int i, length = max(ebitmap_length(e1), ebitmap_length(e2));
+ const ebitmap_node_t *n1, *n2;
+ ebitmap_node_t *new, *prev = NULL;
+ uint32_t startbit;
+ MAPTYPE map;
+
ebitmap_init(dst);
- for (i=0; i < length; i++) {
- int val = ebitmap_get_bit(e1, i) ^ ebitmap_get_bit(e2, i);
- int rc = ebitmap_set_bit(dst, i, val);
- if (rc < 0)
- return rc;
+
+ n1 = e1->node;
+ n2 = e2->node;
+ while (n1 || n2) {
+ if (n1 && n2 && n1->startbit == n2->startbit) {
+ startbit = n1->startbit;
+ map = n1->map ^ n2->map;
+ n1 = n1->next;
+ n2 = n2->next;
+ } else if (!n2 || (n1 && n1->startbit < n2->startbit)) {
+ startbit = n1->startbit;
+ map = n1->map;
+ n1 = n1->next;
+ } else {
+ startbit = n2->startbit;
+ map = n2->map;
+ n2 = n2->next;
+ }
+
+ if (map != 0) {
+ new = malloc(sizeof(ebitmap_node_t));
+ if (!new) {
+ ebitmap_destroy(dst);
+ return -ENOMEM;
+ }
+ new->startbit = startbit;
+ new->map = map;
+ new->next = NULL;
+ if (prev)
+ prev->next = new;
+ else
+ dst->node = new;
+ prev = new;
+ }
}
+
+ if (prev)
+ dst->highbit = prev->startbit + MAPSIZE;
+
return 0;
}
--
2.36.1
